Systematic reviewcited by the Tayebat archivefull text checked A-ORG-09 in-depth review
Diarrhoea after gallbladder removal
Postcholecystectomy diarrhoea rate and predictive factors: a systematic review of the literature.
Overview
Farrugia A et al.. BMJ Open 2022 · PMID 35177439 · DOI 10.1136/bmjopen-2020-046172
About 13% of patients developed diarrhoea after the operation.
Does the study support the specific claim? Yes · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
PCD rate
- How was the study done?
Systematic review
- How many people, animals or samples were studied?
3476
- What was actually found?
13.3%
- How large was the observed effect?
13.3%
- What do the results mean in everyday life?
A common side effect to discuss before surgery
- What are the study's limitations?
Crude pooling of heterogeneous, mostly uncontrolled studies; rates 2-57%; no standard definition
- What does it say about Elawady's specific claim?
Supports informed consent
- Do the results apply to Germany and Europe?
Applicable
- What can explicitly not be concluded from this study?
Causes; exact rate; whether the gallbladder should be kept; that more dietary fat helps
Scientific in-depth review
1. Full reference
- Authors
- Farrugia A, Attard JA, Khan S, Williams N, Arasaradnam R
- Journal
- BMJ Open
- Year
- 2022
- Identifier
- PMID 35177439 DOI 10.1136/bmjopen-2020-046172 · PMC8860059
- Verification
- verified (PMID in archive was wrong, corrected) – PubMed E-utilities efetch, 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- full text
- Conflicts of interest and funding
Funded by Bowel Research UK; competing interests: none declared.
2. Research question
Rate of new-onset post-cholecystectomy diarrhoea (PCD) and its predictive factors
3. Study design and population
- Study design
- Systematic review – Systematic review (PROSPERO CRD42019140444) with crude pooled proportion; no formal meta-analysis
- Population
Adults (18-85 years) after cholecystectomy (1855 laparoscopic, 378 open where reported; 2250 women, 787 men where reported)
- Country
UK authors (University of Warwick); included studies international
- Period
Search up to 29 September 2020; included studies 1987-2018
- Sample size
21 studies (19 observational: 11 prospective, 8 retrospective; 2 RCTs), 3476 patients
- Inclusion and exclusion criteria
Cohort studies or RCTs reporting new-onset PCD; excluded case reports/series, conference abstracts, expert opinion, other systematic reviews, and studies of persistent (pre-existing) symptoms; no language or year limits
4. Methods and endpoints
- Exposure / intervention
Cholecystectomy (laparoscopic or open)
- Comparator
None in most included studies (no control group)
- Endpoints
Primary: rate of new-onset PCD; secondary: predictive factors
- Statistical methods
Simple summation of events across studies (462/3476); no weighting, CIs or heterogeneity statistics (not possible due to lack of data); Newcastle-Ottawa Scale and Cochrane RoB tool; Oxford OCEBM levels
5. Actual results
- Results
462 of 3476 patients (13.3%) developed PCD (conclusion section states 'around 13.1%'); rates ranged 2.1% to 57.2% across studies; assessment from 6 weeks to 4 years, mostly at 3-6 months; in some studies diarrhoea resolved within weeks to months. Predictive factors inconsistent: age <40-50, high BMI, male sex (one study) vs female sex (two), pre-operative heartburn/gastritis, high-fat diet / not following a low-fat diet (two studies); one RCT found no predictors. No difference between open and laparoscopic surgery. Cited: 63.5% of PCD is bile acid diarrhoea.
- Absolute risks
Crude cumulative proportion 13.3% (462/3476), range 2.1-57.2%; no comparison with non-operated patients.
- Authors' conclusion
PCD is relatively common (about 13%) with no well-defined predictive factors; patients should be informed during consent and investigated early for bile acid diarrhoea; larger prospective studies and a standard definition (>3 times/day for >4 weeks) are needed.
6. Strengths
- Registered protocol (PROSPERO)
- Several databases, reference screening, no language limits
- Duplicate independent screening and extraction
- Risk-of-bias tools applied
7. Weaknesses
- Crude unweighted pooling; no CIs or heterogeneity assessment despite 2.1-57.2% range
- Most included studies not powered for PCD, lacked control groups, used non-validated questionnaires and recall (authors)
- No standard definition of diarrhoea; variable timing (6 weeks to 4 years)
- No list of excluded studies, no publication-bias assessment
- Internal inconsistencies (13.3% vs 13.1%; Mertens et al. tabulated as 17/129 = 3.5%)
- Overall low level of evidence (OCEBM 3-4)
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- structured assessment based on the full text by a single reviewer (no formal double review)
- Full formal assessment
- no
- Overall risk of bias
- high
- Rationale
Multiple critical AMSTAR 2 weaknesses (items 7, 11, 15): overall confidence in the review would be rated 'critically low'. The 13.3% figure is a crude descriptive proportion, not a robust pooled estimate. Structured single-reviewer judgement from full text; a formal assessment would require two independent reviewers and the protocol.
| Domain | Judgement | Rationale |
|---|---|---|
| Item 1 PICO components | low | Question and inclusion criteria stated. |
| Item 2 protocol registered before review (critical) | low | PROSPERO CRD42019140444. |
| Item 3 explanation of study designs | some concerns | Cohorts and RCTs included; rationale brief. |
| Item 4 comprehensive literature search (critical) | some concerns | Five databases and reference lists, no language limits; no trial registries or grey literature; 2 papers excluded for unavailable full text. |
| Item 5 duplicate study selection | low | Two independent reviewers. |
| Item 6 duplicate data extraction | low | Two independent reviewers. |
| Item 7 list of excluded studies with justification (critical) | high | Only PRISMA counts; no list of excluded full texts. |
| Item 8 included studies described in detail | some concerns | Table 1 gives design, rate, method, follow-up; little on populations and indications. |
| Item 9 risk-of-bias assessment (critical) | some concerns | Adapted NOS and Cochrane RoB in supplement; results not integrated in main text. |
| Item 10 funding of included studies | high | Not reported. |
| Item 11 appropriate synthesis methods (critical) | high | Simple summation of events across very heterogeneous studies without weighting or heterogeneity assessment. |
| Item 12 impact of RoB on synthesis | high | Not assessed. |
| Item 13 RoB considered in interpretation (critical) | some concerns | Low level of evidence acknowledged in discussion, but 13.3% presented as the headline rate. |
| Item 14 heterogeneity explained | some concerns | Narrative discussion of design, timing, definitions. |
| Item 15 publication bias (critical) | high | Not assessed. |
| Item 16 COI reported | low | Funding and competing interests stated for the review. |
Full-text review (25 October 2026): Added study composition, per-study range 2.1-57.2%, crude unweighted pooling, inconsistent predictors (incl. high-fat diet), funding (Bowel Research UK), internal inconsistencies; AMSTAR 2 items added; bias changed some_concerns -> high (critically low confidence).
9. Assessment of the statistical interpretation
13.3% is an unweighted crude proportion from 21 heterogeneous, mostly uncontrolled studies (range 2.1-57.2%); without control groups it cannot separate surgery-attributable diarrhoea from background bowel symptoms; some cases are transient.
10. Relevance to the specific claim
Documents a real downside of cholecystectomy.
11. Independent contrary findings
12. Transferability to Germany and Europe
UK authors; applicable.
13. Overall methodological judgement
Documents that new-onset diarrhoea after cholecystectomy is a real and fairly common downside that belongs in informed consent, but the rate is imprecise. Two included studies link PCD to high-fat intake, which does not support advice to eat more fat after gallbladder removal.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified (PMID in archive was wrong, corrected) |
| Methodological quality | low |
| Risk of bias | high |
| Precision of results | low |
| Directness | direct |
| Reproducibility | unknown |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Controlled incidence vs non-operated gallstone patients; persistence; standard definition; role of dietary fat.
15. Linked fact checks
- Adenoids, tonsils and the gallbladder are organs that should not be removed; correcting the diet should be the foundation of treatment. – Studies with mixed or unclear results
- After gallbladder removal fat absorption falls, so patients should eat more fat (e.g., 200 g instead of 100 g) such as butter and ghee. – Studies contradicting or limiting the claim
Use by the Tayebat archive
Note: according to the archive, the studies were compiled by the archive operators. Whether Dr. Elawady himself cited this study is not established.
- What the archive says about the study
Listed in the archive bibliography only; the archive gives no specific interpretation.
- A. What was actually studied?
Diarrhoea after cholecystectomy
- B. What did the authors find?
13.3%
- C. What conclusions do the authors themselves draw?
Relatively common; inform patients
- D. What does the archive derive from it?
Supports downsides.
- E. Is this derivation scientifically justified?
Supports a real downside (diarrhoea in about 13%, crude). It does not show the gallbladder should not be removed (no comparison with non-operative management), and two included studies associate PCD with high-fat intake. Note: the archive's original PMID pointed to an unrelated diabetes care study; corrected in register.
- Adequacy of the interpretation (by the archive)
- not applicable